Valerie Aurora has published a great article in LWN about btrfs: "You probably have heard of the cool new kid on the file system block - after all, Linus Torvalds is using it as his root file system on one of his laptops. But you might not know much about it beyond a few high-level keywords - copy-on-write, checksums, writable snapshots - and a few sensational rumors and stories - the Phoronix benchmarks, btrfs is a ZFS ripoff, btrfs is a secret plan for Oracle domination of Linux, etc. When it comes to file systems, it's hard to tell truth from rumor from vile slander. In this article, we'll take a behind-the-scenes look at the design and development of btrfs on many levels."